1. Field of the Invention
The present invention relates to the field of perforating guns used in a down hole oil well environment and in particular to a method and apparatus for using flourescent dyes to determine whether or not a tubing conveyed perforating (TCP) gun charge has fired.
2. Background of the Related Art
During the completion phase of an oil well, perforating guns containing explosive charges are lowered into the wellbore below the casing. Upon detonation the charges blast a hole in the casing, cement and reservoir rock, thereby enabling hydrocarbons in an adjacent hydrocarbon formation to flow into the wellbore for recovery. The conventional method for determining whether the perforating guns have successfully fired is to monitor changes in well bore pressure. Unfortunately, pressure monitoring can only indicate that one or more of the guns have fired (and not always reliably), but cannot determine or whether or not all of the guns have fired successfully. At present there is no known technology available for verifying whether each of the individual perforating guns have fired and hence, there is a lack of reliable quantitative downhole data in this regard. Without useful and reliable data, the decision making process is impaired, with attendant detrimental operational and economic effects. It is imperative that all downhole tubing conveyed perforating guns fire and penetrate the casing to optimize hydrocarbon flow and recovery from the adjacent formation. Thus, there is a need to reliably determine whether each of the perforating guns have successfully fired.